Chain 'n' Gun is a top-down bullet hell coop game.  You and your friend claim to be the best sheriffs in the country. To scilence all who dared to doubt you,  you have accepted a grand challenge. You will fight yourselves through an endless amount of enemies while trying to stay alive. The twist: The two of you are chained together the whole time. 

Tutorial

There is a small tutorial in-game but here is a quick rundown:

The Blue player is controlled with the arrow keys and can dash with the right control key. They fire on Numpad 3.

The Red player is controlled with WASD and can dash with the left shift key. They fire on Space.

There are three different types of Upgrades, one of which will be rewarded after every round.

The first is the whiskey bottle. It grants a huge amount of health to the players.

The second is the ammo upgrade. This allows for more shots to be fired before the players have to reload.

The third is the barrel upgrade. This increases the firing rate of the players.

That's all there is to know so get out there and prove your places as the best sheriffs those fools have ever seen.